Abstract: In this talk I will review the physics of global warming due to increased levels of atmospheric CO2. The current CO2 levels are still very low compared to values that have been the norm since the Cambrian, 550 million years ago. Although CO2 is a greenhouse gas, if there were no other change in the atmosphere, doubling CO2 would cause only about 1 C of warming. Positive feedback from water vapor and clouds is needed to get more alarming figures, but observations suggest that the feedback is not very important. Because life evolved at much higher levels of CO2, increasing atmospheric levels of CO2 are likely to be a net benefit to the planet because of increased crop yields and other advantages of a modestly warmer climate."

Bio: Dr. William Happer, a Professor in the Department of Physics at Princeton University, is a specialist in modern optics, optical and radiofrequency spectroscopy of atoms and molecules, and spin-polarized atoms and nuclei. Born July 27, l939 in Vellore, India, Dr. Happer's parents were Lt. Col. William Happer, a Scottish physician in the Indian Army, and Dr. Gladys Morgan Happer, a medical missionary from North Carolina. He received a B.S. degree in Physics from the University of North Carolina in l960 and the PhD degree in Physics from Princeton University in l964. He began his academic career in 1964 at Columbia University as a member of the research and teaching staﬀ of the Physics Department. While serving as a Professor of Physics he also served as Co-Director of the Columbia Radiation Laboratory from 1971 to 1976, and Director from 1976 to 1979. In l980 he joined the faculty at Princeton UniverŽsity. On August 5, 1991 he was appointed Director of Energy Research in the Department of Energy by President George Bush. While serving in that capacity under Secretary of Energy James Watkins, he oversaw a basic research budget of some $3 billion, which in-cluded much of the federal funding for high energy and nuclear physics, materials science, magnetic conﬁnement fusion, environmental science, the human genome project, and other areas. He remained at the DOE until May 31, 1993 to help the Clinton Administration during the transition period. He was reappointed Professor of Physics at Princeton UniŽversity on June 1, 1993, and named Eugene Higgens Professor of Physics and Chair of the University Research Board from 1995 to 2005. In 2003 he was named to the Cyrus Fogg Brackett Chair of Physics. From 1987 to 1990 he served as Chairman of the Steering Committee of JASON, a group of scientists and engineers who advise agencies of the Federal Government on matters of defense, intelligence, energy policy and other technical problems. He is a trustee of the MITRE Corporation, the Richard Lounsbery Foundation, and the Marshall Institute. He chairs of the National Research Council's Standing Committee on Improvised Explosive Devices that supports the Joint Improvised Explosive Devices Defeat Organization. He was a co-founder in 1994 of Magnetic Imaging Technologies Incorporated (MITI), a small company specializing in the use of laser polarized noble gases for magnetic resonance imaging. He invented the sodium guidestar that is used in astronomical adaptive optics. He has published over 200 scientiﬁc papers. He is a Fellow of the American Physical Society, the American Association for the Advancement of Science, and a member of the American Academy of Arts and Sciences, the National Academy of Sciences and the American Philosophical Society. He was awarded an Alfred P. Sloan Fellowship in 1966, an Alexander von Humboldt Award in 1976, the 1997 Broida Prize and the 1999 Davisson-Germer Prize of the American Physical Society, and the Thomas Alva Edison Patent Award in 2000. Dr. Happer was married in 1967 to the former Barbara Jean Baker of Rahway, New Jersey. They have two grown children, James William and Gladys Anne, and six grandchildren. The Happers live in Princeton, New Jersey.